(Ms.Swain) IB Biology- 2.9 Photosynthesis
chloroplast
(in green plant cells) a plastid that contains chlorophyll and in which photosynthesis takes place.
Describe the shape of the curve for an action spectrum.
- Both absorption and action displays peak at the blue (~450nm) and red (~670nm) - Both displays a drop at green/yellow region (~550 nm)
Outline the process of separating pigments using chromatography
1) Place a line of pigment extract from leaf tissue on one end of the filter paper and dip it in an inorganic substance. 2) As the solvent moves up the semi-polar paper, the pigments get moved as well. The components that adhere more strongly to the other paper travels more slowly compared to those which are less adhesive.
State the equation for photolysis.
2H20 --light--> 4H+ +O2 + 4E-
State the chemical equation for photosynthesis
6CO2 + 6H2O ------> C6H12O6 + 6O2
chlorophyll A
A Blue-green photosynthetic pigment that participates directly in the light reactions, which convert solar energy to chemical energy. Chlorophyll a is the primary photosynthetic pigment while chlorophyll b is the accessory pigment that collects energy and passes it on to chlorophyll a. 2.Chlorophyll a absorbs energy from wavelengths of blue-violet and orange-red light while chlorophyll b absorbs energy from wavelengths of green light
photolysis
A reaction taking place in the thylakoid membranes of a chloroplast during light-dependant reactions where two molecules of water are split to form oxygen, hydrogen ions, and electrons Chemical decomposition induced by light or other radiant energy This part of photosynthesis occurs in the granum of a chloroplast where light is absorbed by chlorophyll; a type of photosynthetic pigment that converts the light to chemical energy. This reacts with water (H2O) and splits the oxygen and hydrogen molecules apart.
Define "limiting factor."
Chemicals depend on more than one essential condition, the rate of reaction will be limited by the factor nearest its minimum value. If the factor is changed to make it closer to the optimum, the reaction rate increases, but changing other factors will have no effect as they're not the limiting factor.
Define photolysis. State that the oxygen produced in photolysis is a waste product of photosynthesis
In photosynthesis light dependent reaction, light is converted to chemical energy in the molecules of ATP. Light is not only absorbed by the chlorophyll but water as well. Then there's the presence of light, water splits due to PHOTOLYSIS. Oxygen comes out as waste product.
Define photosynthesis.
The process in which cells synthesize organic compounds (eg. glucose) from inorganic compounds (H2O + CO2) in the presence of sunlight.
State the relationship between wavelength and energy.
The shorter the wavelengths, the more energy there is. The longer the wavelengths, the less energy there is.
grana
a stacks of thylakoids embedded in the stroma of a chloroplast. Grana function in the light reactions of photosynthesis
Distinguish between an action spectrum and an absorption spectrum.
an absorption spectrum Action: Overall rate of photosynthesis acting at each wavelength Absorption: wavelength of light absorbed by each pigment.
autotrophs
an organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.
Define independent variable, controlled variable and responding variable.
*IV*: What you purposely change in an experiment. *DV*: What you measure during the experiment to see if the IV affect it. CV: Make sure only is affecting DV — all other limiting factors are kept co
Describe the shape of the curve for an absorption spectrum.
- Both absorption and action displays peak at the blue (~450nm) and red (~670nm) - Both displays a drop at green/yellow region (~550nm)
carotenoids
An accessory pigment, either yellow or orange, in the chloroplasts of plants. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis. any of a class of mainly yellow, orange, or red fat-soluble pigments, including carotene, which give color to plant parts such as ripe tomatoes and autumn leaves serves two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they protect chlorophyll from photodamage.
Define visible light.
Electromagnetic radiation in the range of 400-7000 nm, which can be detected by the eye and used by plants.
State the primary and accessory pigments found in chloroplasts
Electromagnetic radiation in the range of 400-7000nm, which can be detected by the eye and used by plants.
State the energy conversion that occurs during photosynthesis
Energy can't be created/destroyed. The energy in the form of light is converted into chemical energy in the bonds of carbohydrates.
State that the oxygen produced in photolysis is a waste product of photosynthesis.
In photosynthesis light dependent reaction, light is converted to chemical energy in the molecules of ATP. Light is not only absorbed by the chlorophyll but water as well. Then there's the presence of light, water splits due to PHOTOLYSIS. Oxygen comes out as waste product.
State that (some) prokaryotes, algae and plants carry out photosynthesis.
Prokaryotes were the first to perform photosynthesis around 3.5 billion years ago, they became a part of the algae and plants million of years later
Calculate the Rf value for pigments using pigment chromatography.
Rf value: (distance of pigment traveled)/(distance solvent traveled).
Define pigment.
Substances, often proteins, which absorbs light and therefore color appears to us the ones that the pigment doesn't absorb.
Explain why plants are green.
Sunlight contains all the wavelengths of visible light. The main photosynthetic pigment in plants is the chlorophyll, which appears green because it reflects light most strongly in the green portion of the spectrum. Chlorophyll absorbs light most strongly in the blue portion followed by the red portion of the spectrum.
Action spectra
The efficiency of photosynthesis is not the same in all wavelengths of light. The graph shows the percentage use of the wavelengths of visible light in photosynthesis. Maximum photosynthesis rates are in blue light, with another but lower peak in red light. Green light is used least effectively, only by accessory pigments that absorb some of it is a graph of the rate of a physiological activity plotted against wavelength of light. It shows which wavelength of light is most effectively used in a specific chemical reaction. Some reactants are able to use specific wavelengths of light more effectively to complete their reactions. defines the spectrum of electromagnetic radiation most effective for photosynthesis.
stroma
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water. central cavity that contains appropriate enzymes and a suitable pH for the Calvin cycle to occur -The fluid of the chloroplast surrounding the thylakoid membrane -Involved in the synthesis of organic molecules from carbon dioxide and water -Contains naked DNA, 70s ribosomes, and enzymes involved in the Calvin cycle
Define and state evidence for the "Great Oxidation Event."
The rise in oxygen concentration to 2% about 2.4 billion years ago is known as the Great Oxidation Event. * Banded ion formation in rocks dated between 2.4-2.2 BYO. * Only when iron dissolved in ancient oceans where it was exposed to oxygen resulted in rusting. Due to no other significant sources of oxygen are known, scientists attribute the rise in atmosphere O2 to biological synthesis.
absorption spectra
a spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption of specific wavelengths. defines the spectrum of electromagnetic radiation, or light, plants absorb.This depends on the cellular and molecular build-up of the plant.
visible light
has a range of wavelengths with violet the shortest wavelength and red the longest visible to the human eye
granum
is a singular stack of thylakoid disk
Calvin cycle
is the set of chemical reactions that take place in chloroplasts during photosynthesis. The cycle is light-independent because it takes place after the energy has been captured from sunlight. ATP and NADPH produced by the light reactions are used in the Calvin cycle to reduce carbon dioxide to sugar. ... The Calvin cycle actually produces a three-carbon sugar glyceraldehyde 3-phosphate (G3P). For the Calvin cycle to synthesize one molecule of sugar (G3P), three molecules of CO2 Must enter the cycle.
Photosynthesis
is the way in which plants create their energy via receiving light. is the process by which cells synthesise organic compounds (e.g. glucose) from inorganic molecules (CO2 and H2O) in the presence of sunlight This process requires a photosynthetic pigment (chlorophyll) and can only occur in certain organisms (plants, certain bacteria)
thylakoid disks
part of chloroplast that contain chlorophyll that captures light used in photosynthesis are disk-shaped membrane structures in chloroplasts that contain chlorophyll. Chloroplasts are made up of stacks of thylakoid disks; a stack of thylakoid disks is called a granum. Photosynthesis (the production of ATP molecules from sunlight) takes place on thylakoid disks
List mechanism for measuring the rate of photosynthesis.
• Measuring CO2 uptake • H2O + CO2 -> H+ +HCO3- • Measuring O2 production: • Water displacement • # of bubbles • Measuring biomass: glucose production can be indirectly measure by a change in the plant's weight. After plant tissue has been dehydrated. Iodine staining will detect starch and can be qualified using a colorimeter.
